Ductile filament.



sTArEs PATENT OFFICE.

ORLANDO H. THOWLESS, NEWARK, NEW JERSEY.

DUGTILE FILAMENT.

No Drawing.

- To all whom it may concern Be it known that I, ORLANDO M. Tnow- LESS, a subj'ect'of the King of Great Britain, residing at Newark, in the county of Essex and State of New Jersey, have invented new and useful Improvements in Ductile Filaments, of which the following is a specification. My invention relates to the manufacture of ductile filaments made of refractory metals and more especially filaments made of tungsten.

The object of my invention is to produce filaments to be used in electrical incandescent lamps Which shall be of practically pure material, shall not darken the bulbs While lighted and which shall remain ductile during the operative life of such filaments, although wire suitable for other purposes may be made by means of my method.

To attain this object I first produce what I will term the parent filament, that being a filament formed of one or more metals flashed on a core and the flashing and core drawn down through reducing holes to a filamentary diameter ready to receive a deposit of metal in its turn, in some instances after the core has been removed from the original flashing, which is preferably done previously to the drawing. For instance, to make a tungsten wire filament of substantially pure metal and one that will be ductile during coloring of the bulbs, I take a filament or rod which may be of molybdenum, tantalum or of tungsten or of some other substance capable of withstanding a high temperature without causing any injury to metal afterward deposited thereon and on such a filament or rod (which for future reference I will term the core) I'cause to be deposited a more or less heavy coating of tungsten. This is accomplished by mounting the core between electric terminals in a flashing-jar or other similar Vessel and, after exhausting the air therefrom, admitting therein a mixture of the vapor of a halogen salt of tungsten and a decomposing gas such as dry hydrogen, then causing an electric current to traverse the core to the extent of raising it to a temperature sufiici'ent to cause a decomposition of the mixed vapors and produce a flashing of. tungsten on the core. A halogen salt of tungsten such as the ntachlorid WCL, or the hexachlorid CL, willibe found suitable for the puror other solvents, so that tungsten remains which its operative life with slight disorkit and draw it while heated duc drawing the 'flashed core.

Specification of Letters Patent. .Patentd Aug; 10, 19155. Application filed March 20, 1914. Serial No. 825,879

pose. The flashing may be continued to any desired extent so that a coating of an thickness may be built up as lon as the heatin 1s mamtamed and the su p of the mixe vapors kept up. The flashed c be laced in a lathe or other vsuitable receptac e and the core drille out or otherwise remove such as by acid only a tube of if pure materials have been used Wlll be of pure tungsten free from carbon, oxids or his tun sten tube is then wrong tthat is, heate and worked, swaged and hammered repeatedly while in the heated condition until it loses its crystalline structure, becomes fibrous in character, ductile at normal atmospheric temperatures and is then reduced to filamentary diameter by drawing .it through reducing holes while itris in a heated condition. The heating and worhng of the tungsten tube results in forming it into a structurally solid body which may then be drawn down to filamentary diameter. .,The above is a description of the method by which the parent filament is made and on pieces of the parent filament,"

other filaments maybe built up by depositing metal thereon and from these, when they are reduced to the proper diameter, other filaments maybe produced in like manner and so on indefinitely, one parent filament being all that is necessagy in theproduction of any number of the aments for use so that with onlythe first flashed metal will a basic core be present requiring to be removed. As an illustration of this-J take one of the parent filaments, connect it with electric terminals in thefiashin -jar and deposit a coating of tungsten thereon from the vapors hereinbefore set forth, until the flashing is of the thickness required. I then hot to a diameter suitable for electrical incandescent lamps, reserving a little of the reduced wire on which to flash deposits of tungsten .to

form other filaments.

Instead of removing the basic core from the parent filament, it may remain and be drawn down with the flasheddeoosit and serve as a support-for it and to enhance its or the core may be eliminated by to filamentary diameter, a flashed deposit made thereon and: this drawn down and 'filamentstaken .in it i' nda ba ch i j e their ore may then bored or reamed other impurities.

no lon er be traced under dbposit' of turn receive a deposit and are drawn down. This may be again and again re the original core of the parent the flashing of the later aments.

The wire may be cut into proper lengths, shaped into filaments for electrlcal incandesoent lamps, and, if necessary, may receive a finishing flashing of metal to e palize their resistance should any inequa 1t1es of resistance appear after the drawing.

Tungsten deposition only has herein been described but other refractory metals capahle of heingdeposited may be used-even ductile metals such as tantalum and molybdenum-as the method described produces pure metal, which has'important char acteristics such as uniformity and solidity of construction with a closeness of grain.

The tungsten flashing consists of long crystals, lying radially, the metal being deposited with a dense formation, the purity of the insur'm its freedom from carhon and oxide, there preventing darkem in of the Bulbs and t e fact of the crystals of t the metal is more he deposit being long, easily made into a fibrous body and this together with its urity' causes filaments made by this method to remain ductile throughout their operative life.

In some cases desirable to have a coating of twoor more refractory metals on the-core, in the form of a. flashed alloy .or in layers. The flashing of the alloy may be a cc lished by mixing vapors of the halogen sa ts of two or moremetals with the dry hydrogenand proceeding as previous'lry set forthij For instance, titanium 'tetrachlorid be mixed with hexao'hlorid or penta and of tungsten and hydrogen, or one of the tungsten chlorids may be mixed with tantalum chlorid TaCl, and

hydrogen to form the flashing of an alloy on the core. To flash metals in layers, one of the metals. above may be flashed on the core and then a second metal ma be flashed upon the first flashed metal. his

may be accomplished by first flashing one metal in a. flashing jar and when it is of sufficient thickness exhausting the jar and allowing the vapors of the halogen salt of another metal with h drogen to enter the $12.71 and ocecd as efore, or, after the rst meta has been flashed. on the core, it may be transferred to another far to receive the second metal flashing and this may be repeatedly done the desired thickness "is attained, when it may be hot worked and operated upon. the same as described-for the 11. Other metals besides those mention may be used and any number of diflerent layers of metal may be flashed on the core.

During thc'deposition of the flashing, the core fi ould be mised-te a high incandescent ted until lament can smaller temperature as the metal appears to have a closer grain when deposited at such a temperature. It is also necessary to have pure materials and to see that the reducing gas is dried before mixing it with the vapor of the metal. salt. I

It will be seen that the above method shows that the filaments are not made from metal in a powdered form and held together by a binder and that no sintering or fritting of the particles of the metal is involved, therefore no impurities will enter into its construction provided pure halogen salts of the metals are used and only hydrogen mixed therewith as the reducing agent. The filament will, therefore, be free from carbon or oxid.

The term metal is to be understood as app-lying equally to one metal or a mixture 2. The method of making ductile filaments which consists in depositingreiractory metal on a conductive core, removing the core therefrom and reducing the deposit to a filamentary diameter.

3. The method of making ductile filaments 'consiaing in flashing a deposit of refractory metal on a conductor reducing this to a smaller diameter, flashing metal thereon and drawing the resulting body to a filamentary size. v

4. The method of making ductile filaments consisting in flashing a depositof refractory metal on a metal core, removing the metal 'corc therefrom, reducin the resulting tube to a smaller diameter, ashing a d refractory metal thereon and reducing this body to a filamentary size.

5. The method of making ductile filaments which consists in flashing a deposit of refractory metal on a metallic conductor, removing the metallic conductor therefrom, drawing the resulting tube to a reduced diameter, heating; and working it until it being the resultant. tube to a high temperature,

eposit of comes a substantially solid body and reduc- I working it into a substantially solid wire and reducing? to a smaller diameter.

7. The met d of making ductile filaments which consists in flashing a deposit of refractory' metal on a conductive core, reducing the 7 diameter, selecting lengths therediameter of the flashed core to a from and flashing metal thereon, drawing these flashed lengths to a smaller diameter and alternately repeating these operations until the core is substantially eliminated.

8. The method of making ductile filaments which consists in decomposing a mixture of hydrogen and the vapor of a halogen salt of tungsten in an air-tight vessel in the presence of a heated core, causing a flashing of tungsten to form on the core, removing the core therefrom, working the resultant tube in a heated condition into a fibrous structure and drawing it to a filamentary size.

9. The method of making ductile filaments Which consists in forming a flashing of refractory metal on a conductive core, hot working the flashed body until it becomes fibrous in structure and then reducing its diameter further by hot drawing it through reducing holes.

10. The method of making ductile filaments which consists in forming a dense, coherent and structurally solid flashing of pure tungsten on a conductive core, hot working this flashed body until it becomes fibrous in structure and then reducing it to a filamentary diameter. 7

11. In the manufacture of ductile filaments the steps which consist in flashing metal on a core and hot working the flashed body until it becomes fibrous in structure.

12. The method of making filaments which consists in flashing a refractory metal on a conductive core, then flashing a different metal on the first flashing, eliminating the core therefrom and reducing the resultant tube to a filamentary diameter.

13. In the manufacture of ductile filaments the steps which consist in flashing metal on a conductive core, flashing a different metal on the first flashing and hot working the flashed body until it becomes fibrous in structure.

14. The method of making filaments which consists in decomposing a mixture of the vapors of two or more halogen salts of refractory metals and hydrogen in the presence of a heated core, causing a deposit of the metals to form upon the core, eliminating the core therefrom, working the resultant metal into a fibrous structure and drawing it to a filamentary size.

15. The method of making filaments which consists in depositing an alloy of two or more refractory metals on a metallic core, hot working it into a fibrous condition and reducing it to a filamentary diameter.

16. A wrought filament composed entirely of refractory metal flashing.

17. A filament composed of a wrought refractory metal flashing.

18. A wrought filament composed essentially of a flashing of tungsten.

19. A filament composed of a conductive core having thereon a wrought refractory metal flashing.

20. A wrought filament composed of a conductive core having thereon a drawn flashing of refractory metal.

.21. A wrought filament composed of a metallic core and having thereon a deposit of more than one refractory metal.

22. A wrought filament composed of more than one layer of refractory metal.

ORLANDO M. THOWLESS.

Witnesses:

HERBERT L. THOWLESS, M. V. DIETRICK. 

